import time 
incomplete_sign = 50 #.的数量
print ('='*23+'开始下载'+'='*25)
for i in range (incomplete_sign + 1):
    completed = "*" * i # 表示已完成
    incomplete = "." * (incomplete_sign) * 100 #百分比
    print ("\r{:.0f}%[{}{}]".format(percentage,completed,
incomplete),end="")
    time.sleep(0.5)
print("\n" + '='*23+'下载完成'+'=')    